Key seat tool for well drilling



K. R. STOHN KEY SEAT TOOL FOR WELL. DRILLING sept. 1, 1953 Filed Oct. 22. 1949 INVENTOR.

Kendall R. Stohn BY Y l JMWWMW ATTORNEYS Patented Sept. l, 1953 UNITED STATES EDATENT OFFICE 9 Claims.

This invention relates to well Ibore tools'and more particularly to a tool for use with drill pipe during the drilling of -a bore. v

In drilling wells by a rotary rig, a drill pipe is employed on the lower end of which is the drill bit. Just above the bit are so-called drill collars having considerable weight which is applied in Varying tensity to the drill bit during drilling. These drill collars are approximately the diameter of the bore drilled by the bit and of larger diameter than the drill pipe which extends to drilling rig at the surface. As the Well bore is drilled, it will deviate from a straight line due to varying forces applied during drilling, different slopes of the earths strata being drilled, diierent hardness of formations, etc. Also, the bore being drilled may be deliberately drilled at an angle to the vertical in order to straighten the hole, to drill around certain obstructions or to drill to a point which is not vertically below the surface where the drilling rig is placed to perform the drilling.

When a bore hole has its direction changed, then as the bore is continued to be drilled below the curve in the bore, the drill pipe will have rotational rubbing against the inside of the curve. This rotation-al rubbing will produce a slot having a width about the same as the drill pipe diameter, but smaller than the drilled bore, due to the fact that the slot was made by the drill pipe which is of smaller diameter than the drill bit which made the bore. These slots are part of wh-at is known as a key seat. With the drill pipe extending through these key seats, it is seen that when the drill pipe is withdrawn to change a drill bit or for any other purpose, the drill collars will often be caught by or stuck in the key seat since the diameter of a drill collar is larger than the slot of the key seat. When a drill collar becomes stuck, much diiliculty can occur in freeing it and there can be much loss in time.

One of the objects of the invention is to produce an improved tool for positioning in the drillv or string pipe above the drill collars which can be employed by manipulation of the drill pipe to enlarge a key seat so that drill collars can pass therethrough without sticking when drill pipe is withdrawn from a well bore.

Another object is to produce a tool for use with drill pipe which will be capable of being expanded and thereby cause the enlarging of a key seat.

A further object is to produce an improved tool for use with drill pipe which is capable of expansion to enlarge a key seat and also capable of rotation with the drill pipe so as to ream or skive out the slot of the key seat.

CTI

4 mandrel.

Still a further object is to produce a tool for use with a drill pipe which will normally have a diameter not greater than the drill collars, but which can be expanded at will to a diameter greater than the drill collars so that a passageway in a well bore can be enlarged to thereby permit easy passing therethrough of drill collars.

Yet a further object is to produce a key seat tool for use with a drill pipe which will permit the enlargement of the key seat slot byl an expanding of a sleeve member, together with a simultaneous driving action thereon.

Other objects will become apparent from the following description taken in connection with the accompanying drawing showing a tool embodying the invention.

In the drawings:

Figure l is a view of the tool in its assembled condition ready for insertion in a drilling string;

Figure 2 is an enlarged view, partly in section, showing certain details of the construction of the mandrel and sleeves and the manner of cooperation to accomplish the expanding action;

Figure 3 is a side view of the mandrel;

Figures 4 and 5 are side views, partly in section, of the two sleeves; and

Figures 6 and 7 are cross-sectional views of the tool, said views being taken on the lines 6 6 and 'I--l of Figure 1. I

Referring to the drawings in detail, my improved tool comprises three main parts, namely a mandrel M, an expansible sleeve E and a nonexpansible sleeve N. The mandrel is in the form of a pipe having threaded ends I0 and II and a longitudinal passage l2 therethrough for usual iluid circulation. One portion of the mandrel, to be referred to as the lower portion I3, is of smaller diameter than the remaining or upper portion Ill. The mandrel between the two portions tapers from the larger to the smaller to provide a conical wedge portion I5. The upper end of the mandrel is arranged to be connected by its threads II toa collar` I6 by which connection can be made to drill pipe (not shown). The collar It is of larger external diameter than the mandrel and thereby provides a shoulder I'I at the upper end of the mandrel. The lower end of the mandrel is arranged to be connected by its threads Il] to a collar I8 whereby connection can be made to drill collars positioned above the drill bit or to other drill pipe if desired. This collar is also of larger diameter than the mandrel.

The expansible sleeve E is constructed to be mounted on the upper larger portion I 4 of the Keys I9 are carried by this sleeve (welded in slots) and such are slidably received in longitudinal key slots in the upper portion of the mandrel. The slots are of such length that the sleeve is capable of slidable movement on the mandrel portion I4, but the sleeve will always be rotatable with the mandrel. The lower or inner end of the sleeve E is arranged to extend beyond the conical wedge portion l5 of the mandrel and to cooperate therewith. The inner surface 2| at the extreme lower yend or the sleeve is of a size to slidably fit the lower portion I3 of the mandrel M. Just inwardly of the surface 2l is a conical surface 22 having the same taper as the conical wedge portion on the mandrel and arranged to cooperate therewith. The sleeve E is arranged for expansion over a. substantial portion of its inner end, which expansion will be accomplished by the wedging action of the wedge portion l5 of the mandrel acting on the inner conical surface 22 of the sleeve as relative .longitudinal movement between the sleeve and mandrel .takes place. lThe expansibili'ty of the sleeve .is permitted by providing longitudinal cuts or kerfs 23 in the sleeve. 'These cuts or kerfs are shown as three 'in number, being circumferentially .spaced equally, with a korf between each key 19. These will permit uniform expansion of the sleeve. The kerls extend over a considerable length or the sleeve.

The second non-expans'ible sleeve N is positioned on the lower smaller lportion |'3 of the mandrel. This Vsleeve carries longitudinal keys 24 welded in slots in the sleeve and arranged to be slidably received in longitudinal slots 25 in the mandrel portion 13 so that the sleeve will always rotate with the mandrel. The slots are v longer than the keys, thus permitting the mandrel to slide longitudinally relatively to the sleeve N. "Ille sleeve end is slda'ble suiciently on the mandrel thatits lower end can engage the collar lll on the lower end o'f the mandrel.

The non-expansible sleeve N on the mandrel is arranged to cooperate with the expansible end of the sleeve E so as vto protect said end and also to cover said end when expanded and thus prevent earth or other material from getting into the space between the lower end of the 'expansible sleeve and the mandrel. The sleeve N also cooperates with the lower end of sleeve E to limit the extent the sleeve E can be expanded bythe mandrel. 'This is all accomplished byprovlding the lower 'end of the vsleeve E with an annular ilange `Y2 6 and `the upper lend of the 'sleeve N with .an annular -ilange 21. The flange 25 is of la Asize to be received 'in the llange 21. The juxtapositioned surfaces of `the two ilanges are preferably conical, as shown, and Athese Asurfaces are arranged to be 'spa-'ced apart `when the lower end foi sleeve E iis `in a normal condition, that is, not expanded by the wedging action of the wedge portion |55 of the mandrel. The spacing ofthe flanges will determine lthe extent to "which :the lower end of the sleeve Ecan =be-expanded. With the flange '211 covering flange 26, then when Athe sleeve E is `expanded the space between the expanded -end lol sleeve E andthe mandrel -portion i3 will be completely covered so 'that earth or other material cannot 4easily get into this :space and thereby "prevent the :sleeve E from Y'contracting 'back to normal condition when `the mandrel is -so moved relatively -tc .sleeve E Ito permit fcontracting. The sleeve N also insures lthat the lower end of -sleeveEwill not be exposedito blows from earth material in ithefbore and thus become damaged.

1The expansible sleeve E kis of such length that when the conical surface 22 is engaged with the conical wedge portion l5 of the mandrel and the sleeve is not being expanded, then the upper end of the sleeve will be a predetermined distance from the shoulder end l1 of the upper connecting collar I6 of the mandrel. This predetermined distance is such as to allow the mandrel to have such relative longitudinal movement with respect to the sleeve that the .sleeve will be expanded the desired amount as allowed by the space between the flanges 26 and 2l. In other words, when the mandrel so moves relatively to ,the sleeve E the .shoulder l1 will be brought into engagement with the end of sleeve E and the maximum expansion desired by the sleeve will have taken place.

The external surfaces of the two sleeves E and N have welded thereto ribs 2B and 29, respectively. These ribs are spirally arranged and can be of a special alloy of cobalt, chromium `and tungsten, known commercially as Borad and ""S'telliteJ If desired, the ribs 28 on the expansible sleeve E, where they are welded to the expansible `portion of said sleeve, can be straight so as to .lie between the cuts or kerfs 23. The sleeves E and N are constructed to have the same external diameters. The external diameter of the expansible sleeve E: `is uniform when the sleeve is normal or not being expanded. The overall external diameters of the sleeves, which will include 'the welded on ribs., will be the same or slightly less than the external diameter of the drill collars used with the drill ,bit. When the sleeve E is expanded, its overall diameter at its expanded lower end will be slightly greater than the drill collars so that fit can expand and ream or lstrive akey seat and ,make it large enough so that the drill collars .can be passed therethrough when it is desired to pull the drill string from the well bore for Yany purpose.

Operation In opera-tion, the tool lis preferably placed in the drill string just above the drill collars at the lower endof which is 'the drillb-it. 'The 'connecting colla-r I8 is connected to the top end of the drill collars and the connecting collar lHi is connected to the usual drill pipe. If the dri-ll string should be in crooked bore with the drill bit and collars below the crook or curve Apoint in the bore, it is possible that a key seat maybe form-ed by the drill pipe during drilling operation. Since the drill `pipe is smaller in diameter than fthe drill collars 'and drill bit, this -key seat will be formed lby the turning of the drill pipe on the bore wall 'at the inside of the "crook or curve point. aturally Athis key lseat will have its slot .por-tion of less width than the drill collar diameter'. With this '-k-ey vseat formed (it may not always Abe formed) Yduring drilling, then when the drill pipe is pulled from Athe bore to remove the .drill bit, or 'for any other purpose, my improved `tool will be 'pulled finto the slot Ivof the key seat `ahead of the drill collars. If the tool n will tpa'ss lon through the key Vseat slot, then of course the @drill vcollars .and drill `:bit can be pulled on through, .as 'all :parts are lsubstantially the same diameter. If the .tool wedges and vbecomes stuck .in the slot of uthe 'key seat, :then by proper and easy manipulatinnof the drill .string the ykey seat can be 'roamed or skived `and enlarged so that its slot will become suilicient'ly -wide to permit passage, not only of the tool but the drill collars and drill bit.

The expans'ible sleeve Eof the y'tool will first enter the key slot if the tool is in the drill string as described. At such time both sleeves N and E will be at the lowest possible position on the mandrel with the lower end of sleeve N engaging the collar I8 and sleeve E engaging the top of sleeve E. The conical surface 22 on the inside of sleeve E will be below the conical wedge portion I5. When the tool becomes stuck the drill stem, if desired, may be first rotated. This will rotate both sleeves (if they are not stuck too tight) in the slot if the key seat and because of the spiral ribs a reaming action will take place which will sufficiently enlarge the slot that the tool will be free to be pulled on through.

If the expansible sleeve E becomes so badly stuck that turning is not possible, the slot of the key seat can be expanded and skived This is accomplished by dropping the drill string. When such is done the mandrel will move longitudinally downward with respect to the stuck sleeve E (also sleeve N if stuck with sleeve E) and the conical Wedge portion I will be brought into engagement with the conical surface 22 on the vinside of the lower end of sleeve E. This will expand the lower end of the sleeve E over that portion having the kerfs or cuts 23. As the sleeve E is expanded it will enlarge the slot of the key seat. The drill string may repeatedly be picked up and dropped, as desired, until the key seat is sufficiently enlarged. After any dropping of the string and expanding of sleeve E, the string may be rotated, if possible, and thus begin the reaming action. During dropping of the drill string and expanding of sleeve E the sleeve N will remain in juxtaposition with the lower end of sleeve E as it is generally also stuck in the slot of the key seat along with sleeve E'. This sleeve N will cover and protect the expansible end of sleeve E. During dropping of the drill string to produce expansion of sleeve E there will also be a simultaneous thrust momentum exerted on the sleeves and this will tend to drive the sleeves downwardly in the key seat to "skive out the slot thereof with sleeve E expanded. An impelled driving thrust can be delivered by the connecting collar I6 after full expansion is accomplished if the collar engages sleeve E at or slightly before the full expansion takes place as permitted by the space between cooperating flanges 26 and 21 and the two collars. If no direct forceful thrust is desired, then of course the tool will be so constructed that collar I8 will not engage the top end of sleeve E when full allowable expansion is accomplished.

After the tool has been worked through the slot of the key seat by various manipulations of the drill string, such as lifting, dropping and turning, then the slot of the key seat will be suiciently enlarged so the drill collars and drill bit can be pulled on through. Thus, with the tool in the drill string during drilling, there will always be present the equipment to easily and quickly open up a key seat so that the drill string can be pulled and lowered without any sticking of drill collars and long delays and diilicult operations to free them.

If it should be desired to operate the tool reversely to that described, such can be done by connecting collar I6 to the drill collars and the other end of the mandrel to the drill pipe. With such installation then as the drill string is pulled up and collars N and E get stuck in a key seat, continued upward pulling can be done with simultaneous rotating of the drill string. This will accomplish reaming and expansion simultaneously. If an upward thrust is desired at any time, the string can be lowered and then pulled up rapidly.

It will be noted that the tool is simple in construction, cheap to manufacture and rugged in al1 respects so as to take any severe usage. If it should be desired to prevent any separation of the two sleeves under any conditions, a suitable connection therebetween can be installed which will not interfere with the expanding of sleeve E.

Being aware of the possibility of modifications in the particular structure shown without departing from the fundamental principles of my invention, I desire it to be understood that the scope of the invention is not to be limited except in accordance with the appended claims.

What is claimed is:

1. In a well drilling tool, a mandrel for connection in drill string, sleeve means mounted thereon for rotation therewith but permitting the mandrel to have relative longitudinal movement with respect thereto, said sleeve means being slit to permit expansion, cooperating Wedging surfaces on the mandrel and sleeve for expanding said sleeve means when the sleeve means is held against longitudinal movement and the mandrel is caused to move longitudinally relative to the sleeve means, and means for limiting the extent of relative longitudinal movement of the mandrel and the sleeve means causing expansion of the sleeve means, said last named means including a second sleeve and a. shoulder on the mandrel with the second sleeve interposed between the shoulder and the said slit sleeve means.

2. In a well drilling tool, a mandrel for connection in a drill string, two sleeves slidable and non-rotatably mounted on the mandrel, one of said sleeves being provided with a split end portion adjacent the end of the other sleeve, means for expanding said split end portion by an axial movement of the mandrel relative to the said one sleeve, and a cooperating means on the adjacent ends of the two sleeves for limiting the extent of expansion of the said one sleeve.

3. In a well drilling tool, a mandrel for connection in a drill string, two sleeves slidable and non-rotatably mounted on the mandrel, one of said sleeves being provided with a split end portion adjacent the end of the other sleeve, and means for expanding said split end portion by an axial movement of the mandrel relative to the said one sleeve, said one sleeve having the split end portion provided with a reduced part for reception in an annular flange on the adjacent end of the other sleeve, the reduced part being spaced radially inwardly from the flange when the split end portion is not expanded.

4. A tool for enlarging a key seat made by a rotating drill stem in the wall of an earth bore being drilled, said tool comprising a mandrel provided at its end with connecting structure to embody it in a drilling stem above the drill bit at the bottom thereof and to form thereby a rigid member in said stem, a sleeve surrounding the mandrel and being mounted to permit relative longitudinal movement between it and the mandrel, said sleeve being of an overall external diameter greater than the drill stem with which the tool is to be associated and constructed to have a part expandable to a larger diameter, and cooperating means on the mandrel and the sleeve for causing expansion of the sleeve when held by the key seat and the mandrel is caused 7 ihmve longitudinal relative movement thereto lzyzmanipulationzofzthedrillstem.

5. A tool for enlarging a key .seat :made :by la vlniiatiilg .drill stem .the Wall `of an `fearth .bore being fdrilled, said rtool `:comprising a mandrel provided at 'its end-with connecting structure 'to v.nnihudy:itin fa sdrilling :stem 4above the drill bit atfthe bottom ythereofy and :to :form thereby 'a .rigid member in said stem, asleeve :surrounding .rthe mandrel L.and being fmounted to permit relative longitudinal movement between it and the :mam xrl, satid :sleeve 'being `of .-an overall external diameter greater than the .drill :stem with which 4the 'tool is -.t o be .associated .and constructed to ShavedI partfexpandable .to a larger diameter, cozopenating means .fon :the mandrel and the sleeve for causing expansion of the 'sleeve when held by the key seat and the mandrel .is ncaused to have longitudinal relative movement thereto by :manipulation fof 'the .drill stem, and means for :limiting the .exten-t -of `expansion of the vsleeve and vthe amount of ,relative `longitudinal .move- .ment 1between .the :sleeve and mandrel.

i6. A etool for .enlarging -a key :seat made by a rotating drill stein'in the `vvall of .an earth bore :being drilled, lsaid .tool comprising -a `mandrel provided at its end vWith connecting structure .to embody iit in a drilling stem above the drill blt l,at the bottom thereof .and to form thereby :a rigid-member in said stem, asleeve surround- Y the mandrel Vand ybeing mounted to permit gelative longitudinal Zmovement between it and .-the mandrel, said sleeve being of an overall external diameter greater than .the 4drill stem with which the v--tool .is :to I.be associated and having longitudinal slits in one end portion to permit expansion, vand cooperating 'Wedging means on the 1mandrel and V.the portion of the sleeve having the :slits for causing expansion .of the sleeve when :held :by the key seat and the `mandrel is lcaused `to 'have relative longitudinal `relative @movement thereto by lmanipulation of Ythe drill stem.

7. .A tool .ffor enlarging -a key seat made by a .=ro.tating-d1iill stem `in 4the -vvall of an earth bore being drilled, said tool comprising -a `mandrel .provided iat its .end with connecting structure to embody fit .in Va drilling stem :above the drill Abit fat the bottom thereof .and .to form thereby a rigid member 1n -said stem, a sleeve surrounding the mandrel and being .mounted to permit relative longitudinal movement between it 4and the manldrol, :said sleeve bei-ng 4of an overall external A.diameter `:greater than the drill stem with Avvhich the tool is to Ybe associated `and having longitui diria-l .slits in fone Vend portion Vto permit expansion, cooperating wedging means =.on 4.the ymandrel `and the portion :of the sleeve having the slits for causing expansionof the sleeve when held by -the fkey `seat and the mandrel is -caused to have .relative longitudinal -movement thereto by mamipulation of the drill stem, and means carried f8 ,by the mandrel for surrounding .thefslit end :of the sleeve for limiting ithe extent :of sleeve =ex-- ipansion.

8. A tool for enlarging 1a .key seat ,made by a rotating `drill stem 2in the yWall vof an earth bore being drilled, said tool fcomprisinjg a mandrel Kprovided-,at its end .with connecting structme yto yembody it lin a drilling stem above the drill bit at the bottom thereof and 'to -form therewith ,a rigid member in the stem, a sleeve vsurrounding the mandrel and 'being mounted to permit .relative longitudinal movement :between it -and :the mandrel, said :sleeve being :of :ran overall external diameter greater than the .drill stem with `which rthe tool is to 'be gassociated .and constructed to have a :part expandable '.to fa largerdiameter, .cooperating means on the mandrel and sleeve for causing expansion of the sleeve when .held bythe key sea-tand the mandrelis causedito vhave Vrelative longitudinal movement thereto by imanipulation of the drill stem, and means forcaus- 'ing Vthe mandrel :to fstrike the .sleeve Awith :a driv ing thrust after expansion has taken place.

v9. A tool for enlarging a. .key seat made b y .a rotating drill stem Vin the wall of an 4earth bore being drilled, ;said tool comprising a mandrel provided .at vits end with connecting structure to -embody it in ia drilling sstem above fthe adrll bit at the bottom thereof Iand :to form therewith -a rigid member in the stem, a Ysleeve :surrounding the `mandrel land being Amounted `to permit relative longitudinal movement between it Vand the mandrel, said sleeve r"being .of :an overall yexternal diameter greater than the 'drill stem with which the tool is to be'associatex'l andfconstructe'd to have apart expandable .to fa .larger diameter, :means on the mandrel andthe sleeve `for causing 4expansion of the sleeve when held by the .key seat and the mandrel is caused to have relative longitudinal Tmovement thereto .in one direction by manipulation of thefdrillfstem, and means .on the mandrel for striking the Vsleeve with driving thrust when the dri-ll stem 4is moved Trelatively vto the :sleeve in the .opposite ldirection ,from .that necessary to cause expansion.

.IGINDALL R. SZI'OHN.

References VCited .in the -file of this .patent 'UNITED STATES PATENTS ,Number Name "Date 403,877 Day May 21,1889 475,913 Yorke May '31, 1892 496,317 Mack Apr. 25J 1893 788,620 ,Adkins May "2, .1905

1,3755817 `B10dgett Apr. 26,1921

2,021,223 Church Nov. 19, 1935 2,501,025 Burris Mar. 2l, 1950 OTHER REFERENCES A-l Bit & Tool Com-pany vpublication on Burris Key Seat Wiper. 

